Plastics and elastomers derived from olefins are used in numerous diverse applications, from trash bags to fibers for clothing. Olefin polymers are used, for instance, in injection or compression molding applications, such as extruded films or sheeting, as extrusion coatings on paper, such as photographic paper and thermal and digital recording paper, and the like. Constant improvements in catalysts have made it possible to better control polymerization processes, and thus influence the properties of the bulk material. Increasingly, efforts are being made to tune the physical properties of plastics for lightness, strength, resistance to corrosion, permeability, optical properties, and the like, for particular uses. In addition to chain length and branching, the incorporation of monomers containing functional groups, such as ethers and esters, offers an opportunity to further modify and control the properties of the bulk material. For example the early transition metal catalyst systems (i.e., Group IV) tend to be intolerant to such functional groups, which often causes catalyst deactivation. Accordingly, there is a need for a catalytic process for polymerizing olefins containing functional groups that is more robust than those previously known in the art.
Conventional low density polyethylenes are readily prepared in high temperature, high pressure polymerizations using peroxide initiators. These high pressure free radical systems can also be used to prepare ethylene copolymers containing functional vinyl monomers, but it is important to note that only a small number of monomers can be polymerized in this high energy (e.g. 200.degree. C., 30K psi) process, i.e., vinyl acetate and methyl acrylate.
Certain transition metal catalysts, such as those based on titanium compounds (e.g. TiCl.sub.3 or TiCl.sub.4) in combination with organoaluminum cocatalysts, are used to make high density polyethylene and linear low density polyethylenes (HDPE and LLDPE, respectively), as well as poly-.alpha.-olefins such as polypropylene. These so-called "Ziegler-Natta" catalysts are quite sensitive to oxygen, sulfur and Bronsted acids, and thus generally cannot be used to make olefin copolymers with functional vinyl monomers having oxygen, sulfur, or Bronsted acids as functional groups.
Recent advances in olefin polymerization catalysis include the following:
L. K. Johnson et al., J. Am. Chem. Soc., 1995, 117, 6414 describes the polymerization of olefins such as ethylene, propylene, and 1-hexene using Pd(II) and Ni(II)-based catalysts; PA1 L. K. Johnson et al., J. Am. Chem. Soc., 1996, 118, 267 describes the copolymerization of ethylene and propylene with certain alkyl acrylates and methyl vinyl ketone using Pd(II)-based catalysts; PA1 C. M. Killian et al., J. Am. Chem. Soc., 1996, 118,11664 describes the preparation of olefin homo- and block copolymers from propylene, 1-hexene, and 1-octadecene using a Ni(II)-.alpha.-diimine catalyst and a methylaluminoxane cocatalyst; PA1 L. K. Johnson et al., WO Patent Application 96/23010 discloses the homo- and copolymerization of ethylene, acyclic olefins, and selected cyclic olefins (e.g., cyclopentene) and optionally including selected unsaturated acids or esters such as acrylic acid or alkyl acrylates; PA1 L. Schmerling et al., U.S. Pat. No. 2,570,601 describes the thermal homopolymerization of epoxybutene and the thermal copolymerization of epoxybutene and various vinyl monomers, such as vinyl chloride, vinyl acetate, acrylonitrile, butadiene and styrene. PA1 Brookhart et al., J. Am. Chem. Soc., 1992, 114, 5894, described the alternating copolymerization of olefins and carbon monoxide with Pd(II) cations ligated with 2,2'-bipyridine and 1,10-phenanthroline; PA1 Brookhart et al., J. Am. Chem. Soc. 1994, 116, 3641, described the preparation of a highly isotactic styrene/CO alternating copolymer using C.sub.2 -symmetric Pd(II) bisoxazoline catalysts; PA1 Nozaki et al., J. Am. Chem. Soc. 1995, 117, 9911, described the enantioselective alternating copolymerization of propylene and carbon monoxide using a chiral phosphine-phosphite Pd(II) complex. PA1 or F is a monomer unit derived from 2,5-dihydrofuran; PA1 (i) a monomer unit derived from an olefin monomer selected from at least one compound of formula (I): ##STR3## wherein R.sup.3 and R.sup.4 are independently hydrogen or hydrocarbyl, or R.sup.3 and R.sup.4 collectively form a bridging group K, wherein K is hydrocarbyl, to provide one or more non-aromatic unsaturated carbocyclic rings; PA1 (ii) a monomer unit derived from a monomer selected from methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, styrene, .alpha.-methylstyrene, glycidyl methacrylate, carbodiimide methacrylate, alkyl crotonates, and vinyl acetate; or PA1 (iii) a monomer unit derived from a C.sub.2 -C.sub.20 alkene substituted one or two times with a group selected from C.sub.1 -C.sub.10 alkoxy, hydroxy, phenoxy, or acetate; and PA1 CO is a carbon monoxide monomer unit, S, T, and V represent the mole fraction of the respective monomer units and sum to one, with the proviso that S&gt;0, and V.ltoreq.0.5. PA1 and units of at least one functionalized olefin monomer, produced by the transition metal catalyzed olefin addition polymerization of a corresponding olefin monomer I with one or more corresponding functionalized olefin monomers selected from the group consisting of olefin monomers II, III, IV, VIII, and IX: ##STR6## which have been described in more detail above, more preferably the polymerization of non-polar olefin I with a functionalized olefin monomer of formula II, III, or IV. In a preferred embodiment of this second embodiment, either VEC and DMVDO are present as functionalized monomers. In general, the number of different functionalized monomer units and the number of different non-polar monomer units are independent of each other. Thus, this embodiment includes, as specific examples, a polymer comprised of vinyl ethylene carbonate, epoxybutene, and ethylene monomer units, a polymer comprised of epoxybutene, DMVDO, ethylene, and cyclopentene monomer units, a polymer comprised of epoxybutene, ethylene, and cyclopentene monomer units, and a polymer comprised of vinyl ethylene carbonate and ethylene. PA1 R is hydrogen or hydrocarbyl; PA1 X and Y are independently OAc, OPh, O-alkyl, OH, SH, S-alkyl, CN, or OR.sub.f, wherein R.sub.f is fluorinated hydrocarbyl and Ac is acyl; or X and Y together can form bridging group J, wherein J is --O--, --S--, --N(R.sup.10)CO--O--, wherein R.sup.10 is hydrogen, hydrocarbyl, or substituted hydrocarbyl, ##STR8## wherein W and Z are independently H, hydrocarbyl, or substituted hydrocarbyl. PA1 wherein N is selected from PA1 (i) a monomer unit derived from an olefin monomer selected from at least one monomer (I): ##STR10## wherein R.sup.3 and R.sup.4 are independently hydrogen or hydrocarbyl, or R.sup.3 and R.sup.4 collectively form a bridging group K, wherein K is hydrocarbyl, to provide one or more non-aromatic unsaturated carbocyclic rings; PA1 (ii) a monomer unit derived from monomers selected from (meth)acrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, styrene, .alpha.-methylstyrene, glycidyl methacrylate, carbodiimide methacrylate, alkyl crotonates, vinyl acetate, di-n-butyl maleate, and di-octyl maleate; or PA1 (iii) a monomer unit derived from C.sub.2 -C.sub.20 alkene substituted one or two times with a group selected from C.sub.1 -C.sub.10 alkoxy, hydroxy, phenoxy, or acetate PA1 or F is a monomer unit derived from 2,5-dihydrofuran; PA1 CO is a carbon monoxide monomer unit, S, T, and V represent the mole fraction of the respective monomer units and sum to one, with the proviso that S&gt;0, and V.ltoreq.0.5; PA1 which comprises contacting said monomers, and optionally CO, with a transition metal selected from Pd(II) and Ni(II), wherein said metal is ligated by a bidentate ligand having donor atoms selected from phosphorus, nitrogen or mixtures thereof.
Certain metallocene catalysts are also known to polymerize olefins, such as described in L. Resconi et al., European Patent Application EP 0 729 968 A1 (1996), Y. Abe et al, European Patent application EP 0 729 983 A2 (1996), D. L. Beach et al., World Patent Application WO 96/27621(1996), H. G. Alt et al., U.S. Pat. No. 5,571,880 (1996), H. G. Alt et al., European Patent Application EP 0 745 607 A2 (1996) assigned to Phillips Petroleum Company, and T. Kiyota et al., European Patent Application EP 0 747 400 A1 (1996) assigned to Sumitomo Chemical Company Ltd.
Ziegler-Natta and metallocene catalyst systems, however, have the drawback that they cannot generally be used in olefin polymerization reactions with functionalized monomers. It is known in the art that homogeneous single site transition metal catalysts generally allow for specific control of catalyst activity through variation of the electronic and steric nature of the ligand. Homogeneous catalysts are known to offer several advantages over heterogeneous catalysts, such as decreased mass transport limitations, improved heat removal, and narrower molecular weight distributions. Therefore, it is also desirable that any catalyst system for polymerizing functionalized olefin monomers be capable of operating under homogenous conditions.
None of the references described above teach the copolymerization of olefins with 3,4-epoxy-1-butene (herinafter "epoxybutene"), epoxybutene derivatives, and analogs thereof. Epoxybutene is a readily available compound containing two reactive groups: a double bond and an epoxide. By reaction at one or both groups, epoxybutene can easily be converted into a host of additional olefin containing compounds.
The preparation of epoxybutene and derivatives thereof, and examples of the same, have previously been described in numerous references, including, but not limited to, U.S. Pat. Nos. 4,897,498; 5,082,956; 5,250,743; 5,315,019; 5,406,007; 5,466,832; 5,536,851; 5,591,874; and in U.S. patent application Ser. No. 08/642,544, U.S. Pat. No. 5,681,969 incorporated herein by reference. Reaction at one or both of these sites affords a host of olefinic derivatives, many of which contain versatile functional groups. Polymerization of epoxybutene has been performed using traditional thermal and free radical initiated reactions, however the pendant epoxide group often does not survive the reaction conditions.
Advances in the polymerization of epoxybutene and its derivatives include the following:
Polymerization reactions of epoxybutene, in which the epoxide ring is opened to afford polyethers, are known, such as those described in: S. N. Falling et al., U.S. Pat. No. 5,608,034 (1997); J. C. Matayabas, Jr., S. N. Falling, U.S. Pat. No. 5,536,882 (1996); J. C. Matayabas, Jr. et al., U.S. Pat. No. 5,502,137 (1996); J. C. Matayabas, Jr., U.S. Pat. No. 5,434,314 (1995); J. C. Matayabas, Jr., U.S. Pat. No. 5,466,759 (1995); and J. C. Matayabas, Jr., U.S. Pat. No. 5,393,867 (1995).
W. E. Bissinger et al., J. Am. Chem. Soc., 1947, 69, 2955 describes the benzoyl peroxide initiated free radical polymerization of vinyl ethylene carbonate, a derivative of epoxybutene.
If the double bond in these compounds could be utilized in an olefin polymerization reaction, so that epoxybutene (or a derivative thereof) could be enchained with other non-polar olefin monomer units, such that at least some of the original polar functionality (i.e., the carbonate in vinyl ethylene carbonate or the epoxide in epoxybutene) remained intact, a copolymer could be produced containing functional groups that would provide for a new polymeric material useful by itself or that could be further derivatized by reaction of the pendant functional groups.
Cationic polymerization of vinyl ethers (such as 2,3-dihydrofuran) is known using Lewis acids or proton-containing acids as initiators. These monomers have been shown to polymerize violently through a cationic polymerization mechanism--often at rates orders of magnitude faster than anionic, or free radical polymerizations--in the presence of both Bronsted and Lewis acids (P. Rempp and E. W. Merrill, "Polymer Synthesis," Huthig & Wepf, 2.sup.nd ed, Basel (1991), pp 144-152). Olefin addition polymerization of vinyl ethers via a transition metal mediated insertion mechanism has not been demonstrated.
In addition, the synthesis of alternating copolymers and terpolymers of olefins and carbon monoxide is of high technical and commercial interest. New polymer compositions, as well as new processes to make polymers derived from olefins and carbon monoxide, are constantly being sought. Perfectly alternating copolymers of .alpha.-olefins and carbon monoxide can be produced using bidentate phosphine ligated Pd(II) catalyst systems (Drent et al., J Organomet. Chem., 1991, 417, 235). These semi-crystalline copolymers are used in a wide variety of applications including fiber and molded part applications. These materials are high performance polymers having high barrier and strength, as well as good thermal and chemical stability.
Alternating copolymerization of olefins and CO using Pd(II) catalysts has been demonstrated by Sen et al., J. Am. Chem. Soc., 1982, 104, 3520; and Organometallics, 1984, 3, 866, which described the use of monodentate phosphines in combination with Pd(NCMe).sub.4 (BF.sub.4).sub.2 for the in situ generation of active catalysts for olefin/CO copolymerization. However, these catalyst systems suffer from poor activities and produce low molecular weight polymers. Subsequent to Sen's early work, Drent and coworkers at Shell described the highly efficient alternating copolymerization of olefins and carbon monoxide using bisphosphine chelated Pd(II) catalysts. Representative patents and publications include: U.S. Pat. No. 4,904,744 (1990); Eur. Pat. Appl. EP 400,719 (1990); Eur. Pat. Appl. EP 360,358 (1990); Eur. Pat. Appl. EP 345,854 (1989); J. Organomet. Chem., 1991, 417, 235; and U.S. Pat. No. 4,970,294 (1990).
Recent advances in olefin/CO copolymerization catalysis include the following:
None of these references teach the copolymerization of olefins with carbon monoxide and functionalized olefins, like epoxybutene and related compounds.
Thus, it would be advantageous to have a homogeneous, single site, transition metal catalyst system that would allow for olefin polymerization of functionalized olefin monomers, such as 3,4-heteroatom substituted olefins, in solution, slurry phase or gas phase, or copolymerization reactions of functionalized olefin monomers with nonpolar monomers and, optionally, with carbon monoxide, under mild reaction conditions.